DETECTION OF OPHIDIOMYCES OPHIODIICOLA IN TWO CAPTIVE BOCOURT WATER SNAKES ( SUBSESSOR BOCOURTI ) AND ONE CAPTIVE PUEBLAN MILK SNAKE ( LAMPROPELTIS TRIANGULUM CAMPBELLI )

Retrospective Detection of Ophidiomyces ophidiicola from Snake Moults Collected in Bieszczady Mountains, Poland

Ophidiomyces ophidiicola, the causative agent of ophidiomycosis, poses a potential threat to wild snakes worldwide. This study aimed to retrospectively investigate the prevalence of O. ophidiicola in archived snake moults collected from the San River Valley in the Bieszczady Mountains, Poland, from 2010 to 2012. Using qPCR for O. ophidiicola detection and conventional PCR for clade characterisation, we analysed 58 moults and one road-killed specimen of Zamenis longissimus and Natrix natrix. A novel combination of primers (ITS2L) was used to simultaneously confirm SYBR Green-based qPCR results and perform genotyping. O. ophidiicola has been detected from two Z. longissimus and one N. natrix specimens. The identified clade (I-B) is consistent with those found in wild snakes of eastern Europe and San River Valley, indicating that O. ophidiicola has been present in this region for at least a decade. This study underscores the value of historical samples in understanding the long-term presence of pathogens and highlights the potential role of environmental reservoirs in the persistence of O. ophidiicola. Our findings are crucial for informing conservation strategies for the endangered Aesculapian snake populations in Poland, emphasising the need for ongoing monitoring and habitat management to mitigate the potential impact of ophidiomycosis.

CONTROLLED CLINICAL TRIAL USING TERBINAFINE NEBULIZATION TO TREAT WILD LAKE ERIE WATERSNAKES (NERODIA SIPEDON INSULARUM) WITH OPHIDIOMYCOSIS

Ophidiomycosis (snake fungal disease) is an important infectious disease caused by the fungus Ophidiomyces ophidiicola. To mitigate the disease's impact on individual snakes, a controlled clinical trial was conducted using terbinafine nebulization to treat snakes with ophidiomycosis. Fifty-three wild-caught Lake Erie watersnakes (Nerodia sipedon insularum) with apparent ophidiomycosis (skin lesions present, qPCR positive for O. ophidiicola) were divided into treatment and control groups: treatment snakes were nebulized with a 2 mg/ml terbinafine solution for 30 min daily for 30 d; control snakes received nebulization with 0.9% saline or no nebulization. Weekly physical exams were conducted to assign disease severity scores based on the number, type, location, and size of lesions, and qPCR was repeated after each 30-d course of treatment. Persistently qPCR-positive snakes received multiple nebulization courses. Terbinafine nebulization showed mixed results as a treatment for ophidiomycosis: 29.2% of animals treated with terbinafine showed molecular resolution of external disease, based on antemortem swabbing, following 3-6 mon of daily nebulization; this was significantly more than with saline nebulization (5%), but molecular resolution also occurred in 11.1% of snakes that received no treatment. Terbinafine nebulization did not significantly decrease clinical disease, as measured by disease severity scores. Evaluating molecular response to treatment using fungal quantities, terbinafine nebulization significantly reduced fungal quantity after three or more courses of treatment. These results indicate that, although terbinafine nebulization is a promising treatment for ophidiomycosis, snakes may require multiple nebulization courses and disease may not always resolve completely, despite treatment. This treatment may be most useful in snakes from managed populations that can be treated for several months, rather than wild snakes who are not releasable after multiple months in captivity.

Ophidiomyces ophidiicola detection and infection: a global review on a potential threat to the world’s snake populations

Ophidiomyces ophidiicola (Oo) is one of the most relevant fungal pathogens for snakes. It is the etiological agent of ophidiomycosis, an emerging disease causing dysecdysis, skin abnormalities, crusting cutaneous lesions, and ulcerations. Despite this major tegumentary “tropism”, Oo infection can be systemic and it is capable of inducing visceral lesions. Moreover, ophidiomycosis may lead to abnormalities of reproductive physiology, hunting behavior, and thermoregulation, thus increasing the risks of sublethal effects and predation on affected snakes. Oo seems horizontally transmitted and can induce postnatal mortality. This article reviews published data on Oo detection and infection in all snake species in countries around the world and categorizes these data using new classification parameters. The presence of this fungus has been recorded in 11 states (considering the USA as a whole); however, in four states, the mycosis has only been reported in snakes held in captivity. Detection and/or infection of Oo has been ascertained in 62 snake species, divided into nine families. The taxa have been categorized with diagnostic criteria in order to report, for each species, the highest rank of categorization resulting from all cases. Therefore, 20 species have been included within the class “Ophidiomycosis and Oo shedder”, 11 within “Ophidiomycosis”, 16 in “Apparent ophidiomycosis”, and 15 within “Ophidiomyces ophidiicola present”. We also discuss the significance and limits of case classifications and Oo’s impact on wild populations, and we suggest methods for preliminary surveillance. Standardized methods, interdisciplinary studies, and cooperation between various research institutions may facilitate further Oo screening studies, elucidate the unclear aspects of the disease, and protect ophidiofauna from this emerging threat at the global level.

INNATE IMMUNE FUNCTION IN LAKE ERIE WATERSNAKES (NERODIA SIPEDON INSULARUM) WITH OPHIDIOMYCOSIS

Ophidiomycosis, caused by the fungus Ophidiomyces ophidiicola, poses a threat to the health of wild and managed snakes worldwide. Variation in snake innate immunity, the primary defense against infection in reptiles, may explain the observed variation in ophidiomycosis clinical disease severity among snakes. In this study, two components of the innate immune response were examined in snake plasma. We investigated whether complement activity, as measured by sheep red blood cell hemolysis, and chitotriosidase activity were associated with ophidiomycosis disease severity and time in captivity in Lake Erie watersnakes (Nerodia sipedon insularum). There was no difference in complement-mediated hemolysis or chitotriosidase activities between snakes with varying levels of ophidiomycosis clinical severity sampled in the field. However, among snakes with skin lesions kept in captivity, chitotriosidase activity was significantly higher in snakes with mild disease, compared with snakes with severe disease, and hemolysis activity increased with time in captivity. Overall, Lake Erie watersnakes had higher complement activity, but lower chitotriosidase activity, compared with other reptile species. To our knowledge, this study is the first to describe chitotriosidase activity in a snake species. These results provide mixed evidence of associations between innate immune function and ophidiomycosis severity, and more work is needed to investigate differences among snake species.

DETECTION OF OPHIDIOMYCES OPHIDIICOLA IN THREE FILE SNAKES (ACROCHORDUS GRANULATUS) IMPORTED FROM INDONESIA TO THE MOSCOW ZOO (RUSSIA)

Three file snakes (Acrochordus granulatus) were delivered to the Moscow Zoo (Russia) from Jakarta (Indonesia). Shortly after arrival, multiple white blisters were detected on their bodies. All three snakes died within a month of arrival. On microscopy, arthrospores and mycelium were seen in exudate from the lesions. Ophidiomyces ophidiicola was isolated from two of three snakes and identified by internal transcribed spacer sequencing. Dermatophyte test medium turned red in positive cultures and can be potentially employed for detection of O. ophidiicola, the causative agent of snake fungal disease. This is the first report of O. ophidiicola in Russia and the second reported case of ophidiomycosis in file snakes. The possible source of O. ophidiicola in snakes imported from Southeast Asia is discussed.

RETROSPECTIVE REVIEW OF OPHIDIOMYCOSIS (OPHIDIOMYCES OPHIODIICOLA) AT THE SMITHSONIAN'S NATIONAL ZOOLOGICAL PARK (1983-2017)

A retrospective review of systemic or localized mycotic infections in captive snakes confirmed via biopsy or necropsy from 1983 to 2017 was performed at the Smithsonian's National Zoological Park. Quantitative polymerase chain reaction (qPCR) confirmed infection with Ophidiomyces ophiodiicola (Oo) in 36.8% (n = 14) of the 38 mycotic infections. Infections with Oo were evenly distributed over the 35-y period and lacked a sex predilection. There was a period prevalence of 4.5% of completed snake necropsy or biopsy cases that were Oo positive. Species affected included green anaconda (Eunectes murinus, n = 4), garden tree boa (Corallus hortulanus, n = 1), false water cobra (Hydrodynastes gigas, n = 5), yellow anaconda (Eunectes notaeus, n = 1), eastern milksnake (Lampropeltis triangulum, n = 1), Brazilian rainbow boa (Epicrates cenchria cenchria, n = 1), and eastern diamondback rattlesnake (Crotalus adamanteus, n = 1). Histopathology demonstrated one or more of the following: heterophilic to necrotizing epidermitis with or without granulomatous dermatitis (n = 12), granulomatous pneumonia (n = 5), granulomatous endophthalmitis (n = 1), and subcutaneous-intramuscular fungal granuloma (n = 1). This study documents the presence of ophidiomycosis in a captive collection for almost 40 years, despite current literature designating it a recently emerging pathogen.

Selected Emerging Infectious Diseases of Squamata: An Update

This article details emerging infectious diseases that have devastating impacts on captive and wild squamates. Treatment advances have been attempted for Cryptosporidium infections in squamates. Gram-positive bacteria, Devriesea agamarum and Austwickia chelonae, are contributing to severe disease in captive and now in wild reptiles, some critically endangered. Nannizziposis, Paranannizziopsis, and Ophidiomyces continue to cause fatal disease as primary pathogens in wild and captive populations of squamates and sphenodontids. Nidovirus, bornavirus, paramyxovirus, sunshine virus, and arenavirus have emerged to be significant causes of neurorespiratory disease in snakes. Controlled studies evaluating environmental stability, disinfection, transmission control, and treatment are lacking.